Miniaturization of semiconductor device packages and electronic components is an ongoing goal for design engineers. Reducing a package perimeter or “footprint” results in the increased availability of space on a receiving substrate to which the package is mounted, such as a printed circuit board (PCB). Additionally, the increased availability of space can also allow a decrease in the footprint of the receiving substrate itself, and thus the size of the electronic component.
Other design goals include increasing the speed of an electronic component and decreasing electronic interference of the operating device. Device speed can be improved by decreasing the length of electrical interconnects within a device, which can also result in a decrease in electronic interference.
Flip chip mounting of a semiconductor die or chip onto a receiving substrate has been widely used because a flip chip device can include very short electrical connections between a plurality of bond pads at a perimeter of a semiconductor die and a plurality of landing pads on the receiving substrate. The electrical connections can include a solder bump on each bond pad which is physically contacted with a landing pad on the receiving substrate. After physical contact is established, the solder can be reflowed to electrically couple the plurality of bond pads with the plurality of landing pads. Because the electrical connections are short, the signal delay and cross-signal interference can be small.
Flexible circuits (i.e., flex circuits) including tape automated bond “TAB” circuits can be interposed between one or more semiconductor chips and a receiving substrate to provide a way to reroute electrical connections between the semiconductor chips and the receiving substrate. In one type of device, semiconductor die is mounted in flip chip fashion onto a first side of a flex circuit. A bond pad at a perimeter of the semiconductor die is electrically connected to a first die bonding pad on the first side of the flex circuit, for example using solder. A first end of a conductive active trace on the first surface of the flex circuit is electrically connected to the first die bonding pad and routed across the first surface of the flex circuit to a laterally located via which comprises a single conductive structure which extends vertically through the thickness of the flex circuit to the opposite, second side of the flex circuit. A conductor such as a solder ball is attached to the via on the second side of the flex circuit, and the solder ball can then connect to a landing pad on the receiving substrate, which electrically couples the semiconductor die with the receiving substrate.